The campaigning spirit that secured the dualling of the A11 must be rekindled to make an upgraded A47 a reality, business leaders have been told.

The call came from South West Norfolk MP Elizabeth Truss, who described improvements to the road as “mission critical” for the county, and urged businesses to support MPs’ efforts by applying the pressure to government.

Addressing more than 100 business and education leaders at Norfolk Chamber of Commerce’s annual MPs event at Sprowston Manor, she said the voice of business could help bring forward the start of work on the £300m upgrade, announced in 2014.

“I would suggest we work with all the businesses in this room to make as much noise as possible,” she said.

“What was really successful with the A11 campaign was we had businesses by the side of the road saying, ‘We need this’.”

Highways England is working on a feasibility study for upgrades to six sections of the road, with public consultation expected in 2017.

“We are having meetings but we need some noise from businesses putting strongly-worded letters into government, saying ‘This is mission critical’,” added Ms Truss.

She was supported by Great Yarmouth MP Brandon Lewis and Broadland’s Keith Simpson during a question-and-answer session focusing on economic growth.

In an afternoon of wide-ranging debate, senior figures from the business world challenged seven of Norfolk’s MPs on issues from housing and apprenticeships to exports and the EU referendum.

North Norfolk MP Norman Lamb and North West Norfolk MP Henry Bellingham discussed the need for improved transport and communications infrastructure to promote Norfolk nationally and globally, while Mid Norfolk’s George Freeman and Norwich North’s Chloe Smith asked how to raise aspiration among the county’s young people.

“We underestimate the power of our own voice and our own passion to help MPs,” she said.

“Sometimes you get fed up of talking about the A11, but actually it was business that got it over the line.”

Chris Starkie, managing director of the New Anglia Local Enterprise Partnership, echoed the importance of businesses speaking as one.

“It’s fantastic to have MPs joined up and working together with local authorities, but you need the business voice because it’s the businesses who will generate the wealth which will justify the investment in the first place,” he said.

Do you have a business story? Email mark.shields@archant.co.uk or call 01603 772426.